import random
def get_verification_code():
    verificationcode = ''
    for i in range(4):
        index = random.randrange(0, 4)
        if index == i:
            verificationcode += chr(random.randint(97, 122))
        else:
            verificationcode += chr(random.randint(65, 90))
    return verificationcode
if __name__ == '__main__':
    print('验证码：', get_verification_code())